Composite Cathode Plate for Low-Temperature Power and Thermal Stability
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Solution Overview
Problem
Lithium ion batteries face challenges in simultaneously achieving high energy density, low-temperature power performance, and safety performance due to the poor thermal stability of high-nickel transition metal oxides used as cathode active materials.
Innovation Solution
A cathode plate composition comprising a medium-nickel low-cobalt or cobalt-free transition metal oxide, a high-nickel transition metal oxide, and a lithium-containing phosphate with an olivine structure, which improves thermal stability and low-temperature power performance by distributing the phosphate material among layered transition metal oxide particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-nickel transition metal oxide is used as cathode active material to improve energy density, then energy density is improved, but thermal stability deteriorates and safety performance is reduced
Solution Approach 1:
The patent applies composite materials by combining high-nickel transition metal oxide particles with phosphate material particles to form a composite cathode active material. This composite structure allows the high-nickel material to provide high energy density while the phosphate material provides thermal stability, resolving the contradiction between energy density and safety performance. The composite material integrates the advantages of both materials to achieve simultaneous improvement in energy density and thermal stability.
2Use of energy by moving object
If high-nickel transition metal oxide is used to improve energy density, then energy density is improved, but safety performance deteriorates
Solution Approach 1:
The phosphate material acts as an intermediary substance that coats or surrounds the high-nickel transition metal oxide particles. This intermediary layer provides thermal stability and safety protection to the high-nickel material without significantly reducing its energy density contribution. The phosphate material mediates between the high-nickel material and the battery environment, preventing harmful thermal runaway while maintaining high energy density.
3Reliability
If phosphate material is added to improve thermal stability, then thermal stability is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the cathode active material into distinct particle components: high-nickel transition metal oxide particles and phosphate material particles. Each particle type maintains its own structural characteristics and functional properties. This segmented particle structure allows for simplified preparation processes compared to creating complex solid solutions or intercalated structures, while still achieving the desired thermal stability through the physical combination of materials.
Data Source
AI summary
Disclosed are a cathode plate and a preparation method therefor, and a lithium ion battery, which relate to the technical field of batteries. The cathode plate includes: a cathode current collector and a cathode film provided on the cathode current collector, wherein a cathode active material of the cathode film comprises a first active material, a second active material and a third active material, the first active material is a medium-nickel low-cobalt or cobalt-free transition metal oxide, the second active material is a high-nickel transition metal oxide, and the third active material is a lithium-containing phosphate having an olivine structure. A medium-nickel material and a high-nickel material are compounded, which can improve the energy density, low-temperature dynamic performance and cycle performance of the material; the phosphate material and the layered transition metal material have different discharge plateaus, which can improve the low-temperature power performance of the material.